Improvement in



A. RULLUPE. VanN-Covers'.

N0e 134,447. Patented Dec. 1,1872fA MM uxw u ma l NI'IEU i FATE@ ATE Il IMPROVEMENT `IN VAULT-COVERS..

Specification forming part of Letters Patent No. E34-AMW, dated December 31,1872.

To all whom 'it may concern:

Be it known that I, ALBERT TRoLLoPE, of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement iu Vault-Lights5 and I do declare that the following is a true andaccurate description thereof, reference being had to the accompanying drawing and to the letters of Aor tiles in cast-metal plates, which form the covering of vaults and other subterranean apartments; and the invention has for its object to so construct the tiles, in relation to a camring surrounding cach tile opening in the plate that the tile may be readily locked therey in. The invention consists in the peculiar construction of the glass tiles in connection with and relative to a cam-ring formed on the under side of the tile-plate about the opening for the tiles, so that when they areinserted therein from the top and partiallyT rotated they will be firmly locked in place.

In the drawing, A represents a p'rition of an cast-metal vault-plate having a number of circular apertures, which may be three inches in diameter, more or less,surrounding each opening. A cam-ring, A', is cast on the under side of the plate A. This ring is of less diameter than the opening, and thus forms a shoulder at its bottom, as seen at Fig. 2, through which shoulder there are cut two vertical slots, a, Fig. 1. The under surface of the rings, from each slot a, forms two inclined planes or cams, b, Fig. 1. The tiles for the openings are of glass, their heads" B being cylindrical, Figs. 2 and 3, and resting upon the cam-rings A. The bodies of the tiles are each in the form of-a cylindrical ungula, B', pendent from the head B. At the opposite sides of the part B a lug, c, is cast therewith, which lugs pass through the slots a when the tile is inserted in the cam-ring, and by partially rotating the tile the said lugs pass under the inclined planes b and draw the head firmly down on the cam-ring, between which, however, a rubber gasket or any other suitable packing may be interposed to prevent leakage.

To facilitate the fastening or removal of the tile each is cast with a pair of sockets, d, on the bisecting angle to receive the hook of the spanner shown in Fig. 3, with which they may be easily turned as circumstances may require.

In placing the plates to illuminate a basement, it'should be so done that when the tiles are locked in place their hat sides will face toward the darkest side of the apartment, as the convex head of the tile gathers a great amount of light into the pendent part, which refracts it through its beveled side, and consequentlyfilluminates chiefly in the direc- Jtion in which the beveled sides are made to ace.

What I claim as my invention, and desire to secure by Letters Patent, is-

The means,x substantially as herein described, of securing illuminating-tiles in their platesthat is to say, by two or more lugs cast on the tile and engaging with a slotted cam about the opening in the tile-plate.

ALBERT TROLLOPE.

I Witnesses:

,EDWARD JOHNSTON, CHARLES J. HUNT. 

